Blood velocity monitoring is not currently practical for intensive care unit (ICU) or surgical applications. For non-invasive brain blood velocity monitoring, for example, a transcranial Doppler (TCD) probe must be mounted in a ball joint that is attached to the head by a helmet. The probe must be carefully aimed and fastened in place by an experienced person who knows how to locate the middle cerebral artery. Slight movements cause the probe to lose the blood velocity signal. Moreover, conventional Doppler ultrasound probes used in these devices scan (either mechanically or by using an acoustic phased array) in only one angle (which we will call azimuth), and will map only a single slice of the object being imaged.
Efforts have been made to modify such devices to provide real-time three dimensional (3-D) imaging. However, in order for a two dimensional (2-D) device to provide such imaging normally requires thousands of elements, and must form many thousands of pencil beams every 1/30 second. Sensor cost grows with the number of elements in the array and the number of processing channels. Thus, such devices are cost prohibitive, as well as impractical.
Moreover, no automated procedure exists in current practice for precisely locating the optimum point at which to measure the Doppler signal. Conventional ultrasound Doppler-imaging devices can only measure radial velocity in blood vessels, and not the vector velocity or magnitude of the velocity of the blood.
Accordingly, what is needed is a new and useful Doppler ultrasound device and method that can automatically locate the optimum point at which to measure the Doppler signal, and thus provide medical providers with parameters such as vector velocity, the volume of blood passing through the blood vessel and the Doppler spectral distribution of the blood flow.
What is also needed is a new and useful Doppler ultrasound device and method that does not require it be placed on a patient with precision, and will enable a patient wearing the device to move freely.
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